Development of a Multi-Layered Electrostatic Film Actuator for an Artificial Muscle

研究的目标是通过堆叠薄的薄膜状静电致动器来开发一种静电人造肌肉，一种具有大力密度的肌肉状柔性致动器。静电人造肌肉是由研究人员专门为人造肌肉研制的感应电荷膜致动器构成的。所述感应电荷膜致动器包括具有大量条纹电极的定子膜和涂有高电阻层的滑块膜。本课题研究了薄膜作动器的材料、设计、制造和控制等关键技术，并开发了人造肌肉的原型。在该项目中获得了以下结果：制作了两种感应电荷膜致动器原型。一个有420毫米的电极，另一个有120毫米的电极。两个执行器都成功操作。采用数值电场分析的方法研究了感应式电荷执行器的特性。结果表明，定子上的电极与滑块上的电阻层之间的距离的最佳值为电极节距的1/5。采用420mm -pitch和100mm -pitch电极的薄膜致动器构建了两个静电人造肌肉原型。采用小间距电极的人工肌肉具有更好的性能。其力密度为35N/kg，功率密度为1W/kg。这种力密度与传统的电磁致动器相当。开发了微步驱动方法。在普通方法驱动的感应电荷执行器中，滑块在一次驱动中的位移等于电极节距。微步驱动将分辨率降低到小于电极间距的1/40。

The goal of the research is to develop an electrostatic artificial muscle, a muscle-like flexible actuator with large force density, by stacking thin, film-shaped electrostatic actuators. The electrostatic artificial muscle is constructed from induction charge film actuators newly developed by the investigators specifically for the artificial muscle. The induction charge film actuator consists of a stator film having a large number of striped electrodes and a slider film coated with a high-resistor layer. In this research project, key technologies for the film actuator such as material, design, fabrication, and control techniques are investigated and prototypes of artificial muscle are developed. The following results are obtained in the project.1. Two prototypes of the induction charge film actuator are fabricated. One has 420mum-pitched electrodes and the other has 120mum-pitched electrodes. Both actuators are successfully operated.2. Characteristic of the induction charge actuator is investigated by means of numerical electric field analysis. As a result, the optimum value for the distance between electrodes on the stator and the resistor layer on the slider is found to be 1/5 of the electrode pitch.3. Two prototypes of the electrostatic artificial muscle are constructed using the film actuators with 420mum-pitched and 100mum-pitched electrodes. Better performance is attained by the artificial muscle with electrodes of the smaller pitch. Its force density and power density are 35N/kg and 1W/kg respectively. This force density is comparable to conventional electromagnetic actuators.4. Micro step driving methods are developed. In the induction charge actuator driven by the normal method, the displacement of the slider in one sequence of drive equals to the electrode pitch. The micro step drive reduces the resolution to be less than 1/40 of the electrode pitch.